Apparatus for molding insulating articles



March 1933- w. c. TREGONING 1,901,205

APPARATUS FOR MOLDING INSULATING ARTICLES- Original Filed May '7, 1928 l'l'la -14 of Fig. 1.

Patented Mar. 14, 1933 UNITED S ATES metres PATENT QFFHQE WILLIAM C. TREGONING, OF 'WAUWATOSA, WISCONSIN, ASSIGNOR TO CUTLER-HAMMER, IN (3., OF MILWAUKEE, WISCONSIN,A CORPORATION OF DELAXVARE APPARATUS FOR MOLDING INSULATING ARTICLES Original application filed May 7, 1928, Serial No. 275,768. Divided. and this applicationfiled October 30,

. 1930. Serial No. 492,166. i

This invention relates to improvements in apparatus for moldin insulating articles. More particularly the invention relates to an apparatus for molding lamp socket casings of insulating material although as will appear various other articles comprisin separable parts may be advantageously formed of the desired molding material, in accordance with the invention. 7

An object of the invention is to provide a novel apparatus of the aforementioned character. 7

Other objects and advantages of the invention will hereinafter appear.

This application is a division of my copending application filed May 7, 1928, Serial No. 275,768, which has resulted in Patent No. 1,871,635, dated August 16,1932.

The accompanying drawing illustrates an embodiment of the invention, which will now be described, it being understood that the invention is susceptible of embodiment in other forms without departing from the scope of the appended claims.

In the drawing, Figure 1 is a side elevation of a lamp socket casing comprising body and cap members formed entirely of 'insulatmg materlal in accordance with my 1nven-- tion, the cap and body members being shown in t-elescoped relation, but priorto relative rotary locking movement thereof.

Figs. 2 and 3 are top and bottom plan views, respectively, of the cap member illuse trated in Fig. 1.

Figs. 4 and 5 are vertical sections through the cap member, on the lines 44 and 5'5 of Figs. and 3, respectively.

Fig. body members of the casing in separated relation.

Fig. 7 is a horizontal section on the line Fig. 8 is a fragmentary vertical section showin a earl: of the interlocking connec-' tion between the cap and body membergand Fig. 9 is a fragmentary view, in side elevation, showing one type of molding press or die which maybe employed in the production of one of the separable members of my novel article. 1 v

6 is a perspective view of the cap and Re-ferrin tothe drawing, the numerals and 21 esignate the body and capmembers, respectively, of a lamp socket casing. Each of said cap and body members is formed entirely of a suitable insulating material, preferably of a slightly resilient or slightly flexible character, such as the phenol-for maldehyde condensation product sold under the trade name of ,bakelite. Each of said members ls'also formed from the insulating material by a single molding operation, as

hereinafter more fully described.

As shown the body member 2'0 comprises an upper portion 22 havinga bore or cavity '23 adapted to receivethe' parts of the lamp socket and terminals to beenclosed in the casing, said member also having an integral lower portion 24 of reduced external diameter and of smaller internal diameter to ac commoda-te the usual metallic. screw shell terminal of the lamp socket. Said upper and lower portions are united by an integral beveled portion 25 forming an internal annular shoulder 26 (Figs. 7 and 8) to properly position the lamp socket parts longitudinally of the casing.

It will be noted that the external dimensions of the body portion 20 are substantially proportional to the dimensions of the bore thereof, thus providing a casing wall 27 of substantially the same thickness throughout'the length of the body portion; whereas by molding the casing parts of bakelite or tance fromsaid edge 29." The member 2Q is provided with a notch or slit 30'extend1ng downwardly a predetermined. distance from theupperedge thereof, and also'molded into.- 7

tending downwardly a predetermined dis- Y grally with the member is a projection 31. The upper end 31 of projection 31 is likewise flush with the upper edge of member 20, and one side 32 of said projection 31 is preferably flush with one side of the notch As shown the projections 28 are spaced sixty degrees apart, with the exception of the two projections 28 on'opposite sides, respectively, of the slit 30; said last mentioned projections being spaced one hundred and twenty degrees apart. The member 20 is provided with the relatively narrow slit 30 when the casing is intended to receive parts to provide a keyless lamp socket, and it will be apparent from Fig. 6, for instance, that another projection of the character illustrated at 28 might be molded integrally with the member 20 and located slightly to the right hand side of slit 30. i

It will be understood that the number of projections corresponding to-28 may be increased or decreased as desired, except that a symmetrical arrangement (as defined herein) of such projections must be provided.

As shown the projection 31 extends downwardly considerably farther than the projections 28 and preferablyabout three or four times as far as the latter, said projection 31 being depressible manually or otherwise, through fiexure of a relatively thin region 35 of the wall, to provide for separation of'the body portion 20 from the cap 21 after the interlocking connection therebetween has been effected, as hereinafter described.

The projection 31 also preferably extends radially outward slightly farther than the projections 28, and depression of the former is similarly required to effect initial telescopic relative movement of the body and cap members 20 and 21 during assembly thereof, whereas if desired the upper edge of projection 31 may be slightly beveled. to automatically effect depression of said projeo tion during initial telescoping movement of said cap and body members.

As shown in Figs. 6 and 7 the thickness of the wall of the upper portion :22 of body member 20 is reduced interiorly thereof from the point indicated at 37 to that side of the slot 30 upon which projection 31 is located. Such reduced wall thickness extends downwardly to the internal shoulder 26 (Fig. 7 but it will be understood that a larger or smaller area of the wall may be formed of reduced thickness to provide the desired or required degree of flexibility thereof for the purpose aforementioned.

Body member 20 ispreferably provided 'with" an internal projection having its inner surface 39 flush with the bore of the lower portion 24 of said member and having its flat upper surface 40 flush with the lower end of the slit 30 (Fig. 7). Said projection is also provided with v oppositely arranged vertical shoulders il for cooperation with suitable notch in the socket parts (not shown) to in- 7 sure against rotation of the latter with respect to the casin The body member 20 is preferably molded with its lower portion 24: of the same external dimensions throughout its length, thus providing for molding of the piece between dies of the usual type which are relatively movable unidirectionally, the usual external thread 1-2 being formed therein by well known means to provide for attachment of a correspondingly threaded shade holder of a well known type.

The cap 21 as aforeindicated is composed of a single molded piece of insulating material, and the same comprises essentially the substantially bell-shaped portion 45, the integrally molded insulating collar or bushing 46, and the bayonet grooved portion 47 at the lower end thereof to provide for interlocking engagement thereof with the body portion 20 aforedescribed. The bushing 46 is preferably provided with a bore 4:8 by the molding operation, and a thread 49 may thereafter be cut in said bore to receive a correspondingly threadedend of a conduit or the like of an electrical fixture, r said thread 49 may be formed in the bushing 46 by the molding operation. Bushing 46 may also be drilled and tapped as indicated at 50 (Fig. 4:) to receive a locking set screw (not shown).

Cap 21 is internally hollowed as indicated at 51 to accommodate the usual conducting wires and terminals of the lamp socket, and also to'minim le the amount of insulating material required in forming the cap. Said cap is also provided with a horizontal substantially annular ledge or shoulder 52 adapted to engage the upper edge 29 of body member '20 when the parts are in assembled relation.

A plurality of radially arranged inward projections 53 are also preferably provided to strengthen the cap and also to engage the upper end of the electrical device which is titted into the bod member 20 to insure against longitudinal movement of such device with respect to the casing.

As shown the cap is provided with six bayonet grooves or slots arranged symmetrically around the inner surface of the lower portion 47 thereof. Each of these grooves com- "prises'a branch 54 extending vertically from the lower edge of the cap to the annular shoulder 52 and a horizontal branch 55 extending from the upper end of said first mentioned branch and opening thereinto. The dimensions and are of radial curvature of the respective branches 55 of the bayonet grooves are substantially the same as but slightly greater than the corresponding dimensions and curvature of the projections 28 to provide formovement of the latter into engagement with the former. I 7

Similarly thewidth of the branches 5a is substantially the same as the Wldtll of branches 55, but the height of the-former is preferably about twice as great as the height of the latter. It is to be understood, however, that the dimensions and relative position of the branches 55 might be changed, provided slots. It will be noted, however, that the branches 55 of said slots are not so deep (that is, they do not extend radially outward to the same extent) as the branches 54, andhence the normal thickness of the Wall or portion 47 of the cap will readily accommodate the branches 55 without necessitating an increase in thickness of the cap at these points.

The cap and body members of the casing may be assembled as follows, referring more particularly to the perspective view of Fig. 6. Thus the parts are initially broughttogether in such mannerthat any five of the branches 54 of the bayonet grooves are in alinement with the respective projections 28. Under these conditions, however, the upper surface 31 of projection 31 on body member will be in engagement with the lower edge '59 of cap member 21, and hence the pro ection 31 must be depressed slightly to clear said edge 59. This depressing operation'of projection 31 may be effected manually or otherwise as aforeindicated, and is facilitated by the reduced thickness of the wall ofmember 20 at the region indicated at 35, which is more flexible than the other portions of such wall.

Such fiexure of the region of the wall, moreover, places the latter under strain, but permits telescopic relative movement of the cap and body members until the projections 28 in traversing the branches 54 of the grooves reach the ledge or shoulder 52, at which time'the projections 28 are in alinement with the branches 55 of the grooves and the former maybe moved into the latter by partial rotation of the cap and body members relatively to each other in a cloclrwisedirection. This relative movement of the cap and body members brings the lowerv edges of the projections 28 into engagement with the shoulders 61 respectively of portions 57' whereby said'cap and body members are held against relative longitudinal movement.

, Simila-rl the side ed es 62 of the res active projections 28 are brought into engagement with vertical shoulders 68, of portions 56 whereby further relative rotary movement of the parts in the'same direction is prevented. At the same time such relative movement of the cap and body members causes the side edge 64 of projection 81 to come into alinement witha shoulder 65 forming a side edge of the vertical branch 54 of one of the bayonet grooves, and the projection. 31 therefore snaps into engagement withsaid shoulder to prevent relative rotary movement of the cap and body members in the reverse direction. The cap and body members are thus'posi-- tively locked against relative movement thereofin any direction, whereas such interlocking connection isv provided by simple means formed integrally with'the respective insulating members.

Separation of-the cap and'body members may be effected by temporarily depressing the projection 31 until the edge 64thereof clears the aforementioned shoulder 65' of branch 54 of the groove, whereupon the cap and body members may be partially rotated relatively to each other to bring the several pro ections 28 into alinement' with the cor-* responding vertical branches 54 of the grooves. The cap and body members may then be separated from each other by .a straight pull or reverse telescopic movement thereof. c Fig. 9 illustrates a novel method of and means for molding an insulation article having -a bayonet or like groove therein. it As shown such means comprises a'moldin'g die; or press having a female die member 66 of the 7 9 desired shape or contour toform theexterior surfaces of the article, and a male die memher of the desired shape or contour to form the interior surfaces ofthe article. However, the male diemember preferably comprises a main portion 67 having a plurality of inte ral projections '68 adapted to form the horizontal branches 55 ofthe bayonet grooves aforedescribed, and a plurality of elements 69 adapted to form the vertical branches 54. of such grooves. The elements 69 are carried by a member 70 which is movable relatively to the integral projections 68, preferably in a vertical direction.

' Thus assuming the illustrated positioningof the elements 69 with respect to'projections 68, the" male and femaledie members are brought together with a quantity of plastic insulating material therebetween to be formed thereby. Upon completion of the molding operation and separation of-the female and male die members the moldedartiole will be interlocked with the latter. However, upon vertical movement of the member 70 carrying the elements 69 the 'vertical 5 branches of the respective bayonet. slots in the molded article will be opened, and by cf fecting partial relative rotation of the article with respect to the maledie member, whereby theprojections 68 of the latter are brought-5 r j be formed on the body member of the article with cooperating projections on the cap member. Also it will be apparent that if desired the cap member might be arranged to telescope into the body membembut ordinarily the internal space requirements of the casing render such an arrangement undesirable.

While I have shown my invention as applied to a lamp socket casing comprising insulating cap and body members, it will be understood that the invention is equally applicable to other types of insulating casings, such as pendent switch casings or the like formed of insulating material.

Similarly it will be understood that my novel joint or connection is applicable to many articles of plasticcomposition other than that herein specifically described, wherein it is desired to look a plurality of separable parts against relative rotary and longitudinal movement, provided only that the composition material employed be ofeslightly resilient or flexible character.

Where no part of the electrical means is "required to extend outwardly beyond the wall of the insulating casing (as where a keyless lamp socket is to be provided), such-wall may be made annularly continuous interiorly of the casing, and that portion of the wall which supports the projection 31 may be molded integrally with the body portion of the casing but spaced slightly from the inner continuous portion of the wall, whereby a relatively tight joint is provided between the cap and body members, the other details of the structure being the same as aforedescribed.

- What I claim as new and desire to secure by Letters Patent is:

1. In a device for molding under pressure insulation articles havingbayonct grooves formed in a surface'thereof, the combination with male and female pressure die members, one ofsaid die members having fixed elements adapted to form portions of the groove re-' 'spectively, said last mentioned die member also having elements adapted to form other portions of the grooves, said last mentioned elements being movable relatively to said fixed elements to permit separation of the article from' said die member by sequential rotary and longitudinal movements relatively thereto upon completion of the molding operation. r V

2. In a device for molding under pressure insulation caps having bayonet grooves formed in the inner surface thereof, the combination'with male andfemale pressure die members, said male die member having fixed Y elements adapted to form horizontally extending portions of the grooves respectively, said male die member also having elements adapted to form vertically extending portions of said grooves, said last mentioned ele ments being movable relatively to said fixed elements to permit partial rotation of the molded article with respect to the male die member, whereby the vertically extending portions of said grooves may be brought into alinement with the fixed elements of the male die member to permit separation of the molded article from the latter.

3. Apparatus for molding a hollow insulation article having a plurality of bayonet grooves formed in a peripheral surface thereof and opening to an edge thereof, comprising male and female die members to be brought together in a straight line with a quantity 'of insulating material'therebetween to'be formed thereby, one of said die members having a plurality of sets of relatively fixed and'movab-le elements arranged to form said bayonet grooves and whereby the molded article is positively, interlocked therewith, and means for effecting joint movement of said movable elements in the line of the molding pressure'to clear the edge opening portions of said bayonet grooves, whereby upon separation of said die members from each other the molded article may be removed by sequentipl rotary and longitudinal movements there- 0 at. Apparatus for molding a hollow insulation article having a plurality of substantially L-shaped grooves arranged peripherally in the inner surface thereof and having one arm of each groove extending upwardly from the lower edge thereof and having the other arms of said grooves extending from the upper ends of said first mentioned arms at substantially right angles thereto, comprising male and female die members to be brought together with a quantity of plastic insulating material therebetween to be formed thereby, said male die member having a plurality of integral projections adapted to form the last mentioned arms of said grooves and a plurality of elements adapted to form the first mentioned arms of said grooves, and means for effecting movement of said elements relatively to said projections and in the line of the molding pressure to clear the upwardly extending arms of said L-shaped grooves, whereby the molded article may be readily removed from said male die member by sequ-entialpartial rotation and longitudinal movement of said article with respect thereto.

5. In a device for molding under pressure a hollow insulation article having a plurality of bayonet grooves formed ina peripheral surface thereof andextending from an edge thereof, the combination with male and female pressure die members, one of said die members having a plurality of fixed elements each adapted to form a portion of one of said grooves, said last mentioned die memher also having a plurality of movable elements each adapted to form another portion of one of said grooves, said fixed and movable elements forming a positiveinterlocking connection between their associated die member and the article molded thereby, and means for effecting joint movement of said last mentioned elements relatively to said fixed elements to permit removal of the mold-- ed article from said die member.

In Witness whereof, I have hereunto snbscribed my name.

WILLIAM G. TREGONlNG. 

